Field of the Invention
The present disclosure relates to an image forming apparatus for forming an image on a sheet comprising a sheet processing apparatus for performing binding processing on a sheet bundle formed of a plurality of sheets.
Description of the Related Art
As a post-processing apparatus of the image forming apparatus, a sheet processing apparatus is widely used. The sheet processing apparatus is an apparatus which performs binding processing using a stapler on a sheet bundle formed of a plurality of sheets having formed an image by the image forming apparatus. The sheet processing apparatus automatically binds the sheet delivered from the image forming apparatus. In this specification, such binding processing is called “online-stapling”. Further, the sheet processing apparatus may comprise an opening into which a user can manually insert the sheet bundle. In this case, the sheet processing apparatus binds the sheet bundle inserted into the opening. In this specification, such binding processing is called “offline-stapling”.
Japanese Patent Application Laid-open No. H02-38265 discloses a post-processing apparatus of an image forming apparatus. In the post-processing apparatus, a stapler is configured to be movable so that the online-stapling and the offline-stapling can be performed with one stapler, which reduces cost. The post-processing apparatus moves the stapler when performing the online-stapling and the offline-stapling and performs the binding processing at different positions.
By decreasing a distance between a position where the stapler performs the online-stapling (online-stapling position) and a position where the stapler performs the offline-stapling (offline-stapling position), a size of the sheet processing apparatus can be reduced. However, if the size of the sheet processing apparatus is reduced, the sheet bundle inserted into the opening is positioned on a moving path of the stapler. Thereby, if the stapler moves in a state in which the sheet bundle is inserted into the opening, the stapler interferes with the sheet bundle. Due to the interference of the stapler with the sheet bundle, the sheet is damaged. This also causes an error of the stapler.
In response to an image forming request including the online-stapling, the image forming apparatus starts to prepare for image formation. When the image forming apparatus moves the stapler from the offline-stapling position to the online-stapling position, if the sheet bundle is inserted into the opening, the moving stapler interferes with the sheet bundle, which damages the sheet bundle. On the other hand, if the image forming apparatus waits for the movement of the stapler until the sheet bundle is removed, the image forming apparatus idly rotates component during a time period until the sheet bundle is removed while the image forming apparatus is preparing for the image formation. Due to prolonged idle rotation, a surface of a photosensitive drum is scraped and developer is deteriorated, which influences a lifetime of the component. Thereby, an image forming apparatus capable of preventing the damage of the sheet bundle and preventing the idle rotation of the component even in a case where the stapler interferes with the sheet bundle when moving the stapler while preparing for the image formation is required.